Novel use of lipolytic enzyme for formation of anti-fingerprint coating, method of forming anti-fingerprint coating, substrate comprising the anti-fingerprint coating formed by the method, and product comprising the substrate

ABSTRACT

Provided are a novel use of a lipolytic enzyme for forming anti-fingerprint coating, a method of forming anti-fingerprint coating including treating a substrate with a composition comprising the lipolytic enzyme, a substrate including the anti-fingerprint coating formed by the same method, and a product including the same. The anti-fingerprint coating can reduce contamination of display devices, appearances of electronic devices or building materials by fingerpris.

TECHNICAL FIELD

The present invention relates to a novel use of a lipolytic enzyme forforming anti-fingerprint coating capable of providing a self cleaningfunction to a surface of a substrate, a method of forminganti-fingerprint coating using the lipolytic enzyme, a substrateincluding the anti-fingerprint coating formed by the same method, and aproduct including the same.

BACKGROUND ART

Contamination caused by fingerprints is one of the most frequentcontaminations occurring on various display devices, high-glossyelectronic devices or building materials. Such contamination is clearlyvisible and causes a defect in the appearance of a product. Recently, asthe fingerprint contamination on a surface of a display device hasincreased with the development of touchscreen interface technology ofelectronic devices, there is an increasing demand for resolving theproblem of the fingerprint contamination on the surface of displaydevices. However, until now, no technology of realizing anti-fingerprintcoating has been actually developed, although anti-contamination coatinghas just been developed in the sense of easy cleaning.

For example, WO09/072738 discloses a anti-fingerprint coatingcomposition for a stainless steel external case of an electronicappliance, which contains 27.6 to 36.2 parts by weight of polysilicate,10.6 parts by weight or less of one resin selected from epoxy and vinylresins, 21.2 to 42.6 parts by weight of colloidal silica, and 10.6 partsby weight or less of an additive composed of at least one selected fromthe first group consisting of —OH, —NH₂, and —COOH and at least oneselected from the second group consisting of -CnF_(2n+1), —SiR₃.

U.S. Pat. No. 20020192181 discloses an anti-contamination composition,which includes a cured or crosslinked polymer having noperfluoropolyether moieties, and a fluid fluorinated alkyl- oralkoxy-containing polymer or oligomer.

However, the above-mentioned anti-contamination film uses fluorine-basedcoating, such that a contaminant transferred to its surface is easilywiped due to low surface energy. Since the anti-contamination film doesnot have a self-cleaning function, that is, a function of activelyreducing transfer of fingerprints or decomposing fingerprints, theappearance may not be improved without wiping the contaminant off.

A conventional anti-fingerprint film can be applied only to a steelplate used for an external case, and has a limit in application to aproduct requiring high light transmittance such as a display device.

Meanwhile, a coating solution, a coating layer, and a coating methodusing the same were also developed in the self-cleaning sense using anenzyme. However, the coating solution, layer and method have beendeveloped to prevent adherence of marine microorganisms to the bottom ofa ship, but not to reduce contamination caused by fingerprints ondisplay devices, the appearances of electronic devices, and buildingmaterials.

For example, a self-polishing, anti-contamination coating composition isdisclosed in U.S. Patent No. 2008/0038241, and a method of preventingcontamination of an underwater device by marine microorganisms isdisclosed in U.S. Pat. No. 5,998,200.

That is, in the self-cleaning sense using an enzyme, the conventionalcoating solution, layer or method has a mechanism of previously removingan adsorbent material produced by marine microorganisms to preventmarine microorganisms from adhering to the bottom of a ship or removinga contaminant with the adsorbent material, but this mechanism is notassociated with the decomposition of the fingerprint contaminant.

As far as the present inventors know, there is no technology ofanti-fingerprint coating in the self-cleaning sense, which can be usedto provide an anti-fingerprint property to the surface of a displaydevice.

TECHNICAL PROBLEM

The present invention is directed to a technique of removing, with nohiding or wiping of, fingerprints by decomposing components of atransferred fingerprint using an enzyme and reducing a deviation in aphysical property between the fingerprint components.

The present invention is also directed to a method of forminganti-fingerprint coating which may reduce transfer of fingerprints andhave a fingerprint decomposing property, a substrate including theanti-fingerprint coating prepared according to the same method, and aproduct including the same.

Technical Solution

The present inventors have made much research on a method of forminganti-fingerprint coating capable of providing a self-cleaning function,not simply forming an anti-contamination coating providing an easycleaning function. In detail, in consideration that the fingerprint ismostly composed of lipids, the present inventors have assumed that whena lipolytic enzyme is coated on a substrate, transferred fingerprintsmay be reduced by the reaction of the enzyme. Accordingly, the presentinventors have confirmed whether such coating provides ananti-fingerprint property by examining a change in a physical propertyof the fingerprint transferred to the lipolytic enzyme-coated substrate.

While major components of a fingerprint are sweat and sebum, thefingerprint is also composed of dead skin cells from the skin andcontaminants such as dusts from an external environment. Among them, ithas been known that the main cause leaving stains on an appearance of aproduct such as an electronic device is sebum, which is composed oflipids including triglycerides, wax monoesters, fatty acids, squalenes,cholesterols, cholesteryl esters, etc. (P. W. Wertz, Int. J Cosmet. Sci.2009, 31: 21-25). Among the components of the sebum, the triglycerideand wax monoester account for nearly 70% of the total content of thesebum. These components have a structure in which several fatty acidsare bound by ester bonds. When the ester bonds are broken down, thesebum is mainly decomposed into fatty acids, especially, oleic acids,leading to an increase in homogeneity and conversion into lowermolecular weight materials. As a result, the sebum may be completelyreleased from a product by decomposing the oleic acids into lowermolecular weight materials or modifying the oleic acids to increasevolatility.

Therefore, the present invention is directed to a novel use of alipolytic enzyme for forming anti-fingerprint coating, that is, a methodof forming anti-fingerprint coating using a lipolytic enzyme.

More particularly, the present invention is directed to a method offorming anti-fingerprint coating including treating the substrate with acomposition comprising a lipolytic enzyme.

In the present invention, the lipolytic enzyme includes any enzymeshaving a characteristic of hydrolyzing lipid components of a fingerprintsuch as triglycerides, wax monoesters, fatty acids, squalenes,cholesterols and cholesteryl esters.

An example of an enzyme having an activity to hydrolyze ester bonds atroom temperature is a lipase. The present invention is not limited tothe kind or origin of the lipase, and thus any type of lipase may beused as the lipolytic enzyme according to one embodiment of the presentinvention. To obtain a high degree of hydrolysis with respect to thetriglyceride and wax monoester, which are the main components of thesebum, a lipase non-specifically acting at any position may be used.Currently, various lipases produced using microorganisms may becommercially available from Novozymes or Amano Enzyme, and a lipase maybe produced using a transformer into which a backbone gene of the lipaseis inserted.

In addition to the lipase, the enzymes having a lipolytic activity arewell known in the art. For example, a considerable number of proteasesare known as lipolytic enzymes having lipolytic activity, and cutinasesare also known to have lipolytic activity.

A composition comprising a lipolytic enzyme for forming anti-fingerprintcoating may also include at least one enzyme selected from the groupconsisting of a protease, an amylase, a cellulase and a lactase. Forexample, to decompose various kinds of proteins smeared by afingerprint, a protease may be immobilized on a surface of the product.The protease is used to break peptide bonds between proteins and therebyremove contamination. In addition, to remove components of sweat andcomponents derived from various external contaminants, an enzyme such asan amylase, a cellulase or a lactase may be used.

In addition to the enzyme, the composition may further include amaterial capable of stabilizing the enzyme. For example, the compositionmay include a buffer such as a phosphate buffered saline (PBS), apotassium phosphate buffer, or a sodium phosphate buffer. To retain theactivity of the enzyme, a polyhydric alcohol such as polyethyleneglycolor propylene glycol may be coated as the polymer on a substrate with theenzyme, or polyurethane, acryl-based organic material or asiloxane-based organic/inorganic compound may be coated on a substratewith the enzyme.

The composition other than the above-mentioned enzyme may be coated onthe substrate with the enzyme at a time, or the enzyme and thecomposition may be sequentially coated on the substrate. That is, thecomposition excluding the enzyme may be coated on the substrate, andthen the enzyme may be coated thereon by adsorption or covalent bonds.

Meanwhile, moisture is required for a lipolytic enzyme to hydrolyzelipids. Since the fingerprint includes moisture in addition to thelipid, there is no need to supply the moisture. However, to supply moremoisture and improve stability of the enzyme, a hydrogel component maybe included in the composition or coated on the surface of thesubstrate. To prepare the hydrogel component, a material having both across-linker containing at least two double bonds and a hydrophilicfunctional group may be used. Such a component may include ethyleneglycols or acrylamides having a multifunctional group. Due to the supplyof the moisture and the stability of the enzyme by hydrogel coating, thehydrolysis of the triglyceride and wax monoester may be furtherpromoted.

Meanwhile, the present invention is not limited to the substrate havinganti-fingerprint coating, and thus any type of substrate is applicable.For example, products requiring the anti-fingerprint coating areproducts that are often contacted with hands in everyday life, includingdisplay devices, appearances of electronic devices, and buildingmaterials. These products have a surface formed of plastic or glass, ora surface treated by gloss coating such as UV coating or protectivecoating. In one embodiment, the substrate may be formed of plastic orglass. For example, the substrate may include at least one polymerselected from polyester, polypropylene, polyethyleneterephthalate,polyethylenenaphthalate, polycarbonate, triacetylcellulose, olefincopolymer, and polymethylmethacrylate, or glass. The substrate may betreated on its surface by various coating methods such as gloss coating,protective coating, paint coating, and hydrogel coating.

The present invention is not particularly limited to a method oftreating the substrate with the composition including a lipolyticenzyme, and thus any method known in the art will be used. A method ofimmobilizing an enzyme is known in the art. For example, a lipolyticenzyme may be introduced to the surface of the substrate by adsorption,covalent bonds or encapsulation.

The adsorption refers to adherence of the lipolytic enzyme to thesurface of the substrate or a coating layer of an enzyme-freeanti-fingerprint coating composition by physical cohesion. A proteinconstituting the enzyme has strong adsorption to a surface of a materialalone. Thus, the lipolytic enzyme may be immobilized to the surface ofthe substrate by adsorption with no use of an additional treatmentprocess. The following embodiment shows that the immobilization of thelipolytic enzyme by adsorption provides excellent stability.

To introduce the lipolytic enzyme to the surface of the substrate, thereare various known techniques of forming covalent bonds between thesubstrate and the enzyme or between the coating layer of the enzyme-freeanti-fingerprint coating composition and the enzyme. The techniques usea cyanogen bromide, an acid azide derivative, a condensing reagent,diazo coupling, alkylation, and carrier crosslinking.

For example, the carrier crosslinking technique is a technique offorming covalent bonds between a functional group present on the surfaceof the substrate and a functional group present on the surface of thesubstrate and a functional group present on the lipolytic enzyme using abifunctional crosslinker. Since the lipolytic enzyme has variousfunctional groups in addition to an amino group and a carboxyl group, ifa functional group capable of covalently binding to these functionalgroups is present in the surface of the substrate, the covalent bondsmay be easily formed using the bifunctional crosslinker. Here, thefunctional group present on the surface of the substrate may be afunctional group originally present on the substrate or a functionalgroup introduced to the surface of the substrate to form the covalentbonds or included in the enzyme-free anti-fingerprint coatingcomposition. For example, when the substrate is formed of plastic, thefunctional group present on the surface of the substrate may be directlyused, and a desired functional group may be introduced to the surface byplasma or primer treatment. When the substrate is formed of glass, thefunctional group may be introduced to the surface by self-assembledmonolayer (SAM) treatment using a siloxane-based organic compound, butthe present invention is not limited thereto. As a functional group forforming covalent bonds with the enzyme, an amino group, an amide group,a carboxyl group, an aldehyde group, a hydroxyl group, or a thiol groupis used, and the functional group present on or introduced to thesurface of the substrate may vary according to the kind of thesubstrate.

In one embodiment, the covalent bond may be formed by a processincluding a) treating a substrate having at least one functional groupselected from the group consisting of amino, amide, carboxyl, aldehyde,hydroxyl and thiol groups with a solution including a bifunctionalcrosslinker; and b) dipping the substrate in a buffer including thelipolytic enzyme.

As a bifunctional crosslinker used to induce formation of the covalentbonds, a bis-imidoester, bis-succinimidyl derivative, bifunctional arylhalide, bifunctional acrylating agent, dialdehyde, or diketone may beused, but the present invention is not limited thereto. An exemplaryembodiment of the present invention shows the covalent bond beinginduced using dialdehyde, for example, glutaraldehyde.

In another embodiment, the covalent bond may be formed by dipping thesubstrate having an epoxy group at a surface thereof in the bufferincluding the lipolytic enzyme. Furthermore, as the substrate undergoingthe above process is treated with heat or UV at a level in which theheat or UV does not degrade the activity of the enzyme, the enzyme maybe more strongly immobilized.

A method of immobilizing the enzyme using the covalent bond as describedabove will be described in further detail with reference to thefollowing exemplary embodiments.

In addition, the encapsulation refers to a method of immobilizing theenzyme by trapping the lipolytic enzyme between other materials. In anembodiment, the encapsulation may be performed by coating the surface ofthe substrate with a gel matrix, microcapsule, hollow fiber or membrane,and introducing the lipolytic enzyme. For example, a membrane formed ofcellulose such as cellulose nitrate or cellulose acetate, polycarbonate,nylon, or fluororesin such as polytetrafluoroethylene may be used.

The coating of the substrate with a gel matrix, microcapsule, hollowfiber or membrane and the introduction of the lipolytic enzyme may besimultaneously or sequentially performed. In other words, the surface ofthe substrate is first coated with the gel matrix, microcapsule, hollowfiber or membrane, and the substrate is then dipped in the bufferincluding the lipolytic enzyme. Otherwise, the lipolytic enzyme may beintroduced as soon as the surface of the substrate is coated with thegel matrix, microcapsule, hollow fiber or membrane. For example, for theencapsulation technique using the gel matrix, the gel matrix may becoated and cured, and the enzyme may then be adsorbed, or when a solsolution is prepared in a sol-gel reaction, the enzyme may be added toprepare a mixed solution and the substrate may be coated with the mixedsolution and then cured.

Among the methods, the encapsulation using the gel matrix is moredesirable to retain and further promote the activity of the enzyme. Anykind of gels ensuring a mechanical strength and an optical property maybe applied. For example, the substrate may be primarily coated with acoating layer prepared by a sol-gel method using tetramethoxysilane(TMOS), tetraethoxysilane (TEOS) or glycidoxypropyl trimethoxysilane(GPTMS) or a hydrogel forming a double network by reinforcing amechanical strength of polyethylene glycol, and the enzyme is thenencapsulated into the primary coating. Further detailed description willbe provided in the following exemplary embodiment.

As the buffer including the lipolytic enzyme used in the above-describedmethods, a PBS buffer, potassium phosphate buffer, or sodium phosphatebuffer may be used, and the present invention is not limited thereto. Anamount of the lipolytic enzyme included in the buffer is determined inprinciple as an amount at which the surface of the substrate to beimmobilized may be covered with a monolayer. A generally used lipolyticenzyme is composed of a small amount of enzyme and additives includingan excess of an extender such as dextrin or lactose and a stabilizer.Thus, the amount of the enzyme to be added is determined based only onthe content of the protein. In the case of the covalent bond, the amountof the enzyme to be added may be determined by calculating a content ofthe protein corresponding to the functional group of the surface of thesubstrate, and in the cases of the adsorption and encapsulation, anamount of the enzyme to be added, which is 3 to 10 times the content ofthe protein capable of covering the surface of the substrate, may bedissolved in the buffer.

The present invention is also directed to a substrate including theanti-fingerprint coating formed by the above-described method. As seenfrom the following exemplary embodiments, the substrate including theanti-fingerprint coating to which a lipolytic enzyme is immobilizedaccording to the method exhibits an anti-fingerprint characteristicbecause of decomposition of fingerprints and a decrease in transfer offingerprints. Such anti-fingerprint coating may be stacked on thesurface of the substrate in a single layer or multiple layers. Theanti-fingerprint coating may be formed on the surface of the substrateto have a thickness of 20 nm to 200 μm. A single layer of coating may beformed with a thickness of 20 nm, and the coating may be carried out upto a thickness of 200 μm according to the kind and content of thecoating composition. However, the thickness of the coating needs to beadjusted to a thickness level in which the optical property required forthe substrate is not degraded. When the thickness of theanti-fingerprint coating layer is less than 20 nm, the decomposition ofthe fingerprint components may be limited, and when the thickness of theanti-fingerprint coating layer is more than 200 μm, the opticaltransmittance may be degraded.

To maximize a spreading effect of the fingerprint components, theanti-fingerprint coating layer may have a surface energy of 20 to 50mN/m. When the surface energy of the anti-fingerprint coating layer isless than 20 mN/m, the fingerprint components may not spread, and whenthe surface energy of the anti-fingerprint coating layer is more than 50mN/m, the fingerprint may be difficult to easily remove. Here, when alipase is, for example, coated as the enzyme, the coating layer has asurface energy of 30 to 50 mN/m in which the spreading effect of thefingerprint is maximized. As a result, since the transfer of thefingerprints is reduced, the range of the surface energy may bepreferred.

The present invention is also directed to a product including thesubstrate including the anti-fingerprint coating. The product includingthe substrate including the anti-fingerprint coating according to thepresent invention may be a product that is often contacted with hands ineveryday life, and the present invention is not particularly limited tothe kind of the product. For example, the product may include displaydevices, electronic devices, or building materials. The display devicemay be one selected from the group consisting of a liquid crystaldisplay device (LCD), an organic light emitting diode (OLED), and aplasma display device panel (PDP). Since currently-supplied portabledisplay devices have a touchscreen-type interface, the introduction ofthe anti-fingerprint coating according to one embodiment of the presentinvention may cause the significant improvement of beauty of theproduct.

The present invention is not particularly limited to a method ofintroducing the anti-fingerprint coating to the product. In other words,the lipolytic enzyme may be directly coated on a substrate surface ofthe product such as the display device, or the film-type substratecoated with the lipolytic enzyme may be adhered to the surface of theproduct.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will become more apparent to those of ordinary skill in theart by describing in detail exemplary embodiments thereof with referenceto the adhered drawings, in which:

FIG. 1 is a graph of haze values measured after fingerprints aretransferred to a substrate including an anti-fingerprint coating formedin Example 1;

FIGS. 2 and 3 are NMR spectrums for decomposition results obtained aftermajor fingerprint components are transferred to substrates includinganti-fingerprint coatings formed in Examples 1 and 2;

FIGS. 4 and 5 are NMR spectrums for decomposition results obtained aftermajor fingerprint components are transferred to a substrate includinganti-fingerprint coating Example 3;

FIGS. 6 and 7 are graphs showing disappearance of fingerprints measuredusing a hazemeter after real fingerprints are transferred to thesubstrate including the anti-fingerprint coating formed in Example 3;

FIG. 8 is a graph showing disappearance of fingerprints measured using ahazemeter after the real fingerprints are transferred when a wiping testis performed on the substrate including the anti-fingerprint coatingformed in Example 3; and

FIGS. 9 and 10 are graphs showing disappearance of a contaminantmeasured using a hazemeter when mixed contaminants are applied to thesubstrate including the anti-fingerprint coating formed in Example 3.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, the present invention will be described with reference toexamples and comparative examples in detail. However, the presentinvention is not limited to these examples.

EXAMPLES Example 1 Immobilization of Lipolytic Enzyme Using CovalentBonds

A lipase was coated on a glass substrate by the following method.

A slide glass whose surface was coated with amino alkyl silane wasreacted in 10% glutaraldehyde solution for 2 hours. Subsequently, theslide glass was lightly washed with distilled water, dipped in a PBSbuffer having 100 mg/ml of a lipase (Amano Enzyme; Lipase PS “Amano” SD;derived from Burkholderia cepacia), and then kept at a room temperaturefor 24 hours. The lipase-immobilized slide glass was sufficiently washedwith running distilled water, and washed in distilled water for 40minutes with gentle shaking. Then, the slide glass was taken out, andblow-dried with compressed nitrogen at a room temperature. Thus, thepreparation of a lipase-coated glass substrate was completed.

Experimental Example 1 Examination of Decrease in Degree of Transfer ofFingerprints by Anti-Fingerprint Coating

Three samples were prepared by transferring fingerprints to thelipase-immobilized slide glasses as shown in Example 1, and measured forhaze values according to time. The results are shown in FIG. 1. Here, asa control glass (without a lipase), a slide glass treated with aminoalkyl silane and glutaraldehyde was prepared for comparison.

When the haze values were measured immediately after the fingerprintswere left (0 hr), it was seen that the lipase-coated substrate shows alower haze value than the control glass, which indicates that thefingerprints was less smeared on the lipase-coated substrate. Also, itwas seen that the haze value is decreased as the fingerprint on thelipase-coated substrate was decomposed with time.

As described above, by an experiment of transferring the fingerprint tothe lipase-immobilized surface, examining the resulting surface using amicroscope, and measuring a haze value, it was seen that thelipase-immobilized surface had a lower degree of transfer of fingerprintthan the surface without the lipase.

Example 2 Immobilization of Lipolytic Enzyme Using Epoxy Group

An immobilizing method using an epoxy group was performed, instead ofthe method of coating a lipase using chemical covalent bonds describedin Example 1. The epoxy group-treated slide glass (superchip glass ES;slide epoxy silane; nunc™) was dipped in a sodium phosphate bufferhaving 100 mg/ml of a lipase, and kept at a room temperature for 4hours. Afterwards, the slide glass was reacted in an oven at 50 to 55°C. for 30 minutes. The slide glass was rinsed 15 to 20 times indistilled water, and washed with a sufficient amount of distilled waterthree times for 20 minutes. The slide glass was blow-dried withcompressed nitrogen at a room temperature.

Example 3 Immobilization of Hydrolase to Gel Matrix by Adsorption

A surface of a substrate was coated with a hydrolase by adsorption usinga gel matrix. According to this method, the gel matrix stabilized theenzyme, such that the efficiency of the enzyme was increased, andfunctional coating could be simultaneously performed using various gelmatrixes. A lipase may be used as the enzyme alone, or in a combinationof lipase and amylase or lipase and protease. First, the gel matrix wascoated on a slide glass using a siloxane-based composition, which wasperformed according to Example 1 disclosed in Korean Patent PublicationNo. 1998-0002185. The gel matrix slide prepared thus was dipped in PBSbuffer having 100 mg/ml of an enzyme, and kept at a room temperature for24 hours. The slide was taken out, washed in the same manner as inExample 2, and blow-dried with compressed nitrogen at room temperature.

Experimental Example 2 Confirmation of Lipolytic Effect byAnti-Fingerprint Coating

To confirm fingerprint decomposing performance from a glass prepared bycoating a lipase by the same chemical covalent bond method as describedin Examples 1 and 2, this experiment was performed using the maincomponent, triglyceride, of a fingerprint. The triglyceride was atriolein, which was coated on a surface of the glass and kept at a roomtemperature for 24 hours. Afterwards, ¹H-NMR analysis was performed toexamine whether the triolein was decomposed or not. As a result, asshown in FIGS. 2 and 3, it was seen that an acid peak which did notappear from the reference (triolein) was observed from the lipase-coatedslide.

Experimental Example 3 Confirmation of Lipolytic Effect byAnti-Fingerprint Coating

To confirm fingerprint decomposing performance from a glass prepared bycoating a lipase with a gel matrix as described in Example 3, anexperiment was performed using the main component of a fingerprint, atriglyceride. Afterwards, ¹H-NMR analysis was performed to examinewhether the triolein was decomposed or not. As a result, as shown inFIGS. 4 and 5, it was seen that an acid peak which was not seen from thereference (triolein) was shown from the lipase-coated slide.

Experimental Example 4 Confirmation of Fingerprint DecompositionPerformance by Anti-Fingerprint Coating

To confirm fingerprint decomposing performance from a glass prepared bycoating a lipase together with a gel matrix in the same manner asdescribed in Example 3, haze values were measured to examine a degree ofdisappearance of a fingerprint really transferred from a palm. Thechange in haze with time was observed for 48 to 96 hours under varioustemperature and humidity conditions using a temperature and humiditytester. The results are shown in FIGS. 6 and 7. The change in haze value(ΔH) with time was exhibited, provided that the haze value (ΔH)increased by fingerprint transfer was set to 100%. Compared to alipase-free sample (shown as “w/o lipase”) prepared in the same manneras described in Example 3, a significant decrease in haze was seen fromthe lipase-treated sample (shown as “w/lipase”).

Experimental Example 5 Confirmation of Fingerprint DecomposingPerformance by Anti-Fingerprint Coating

A wiping test was performed to confirm that immobilization of alipolytic enzyme by adsorption was very stable on a glass prepared bycoating with a lipase together with a gel matrix according to the methoddescribed in Example 3.

A wiped sample was prepared by pressing a glass sample with a weight of1 kg and wiping the glass sample 100 times with a dust-free fabric.Transfer of a real fingerprint was performed on the sample and anon-wiped sample, and then a degree of disappearance of the fingerprintwas examined by measuring a haze value. The change in haze with time wasobserved for 48 hours under conditions including a temperature of 50° C.and a relative humidity of 30% using the temperature and humiditytester. The results are shown in FIG. 8. The change in ΔH with time wasexhibited, provided that the haze value (ΔH) increased by fingerprinttransfer was set to 100%. Compared to the sample (shown as “not wiped”)which was prepared in the same manner as in Example 3 but not wiped, itwas confirmed that no decrease in performance was observed from thewiped sample (shown as “wiped 100 times”).

Experimental Example 6 Confirmation of Fingerprint DecomposingPerformance by Anti-Fingerprint Coating

Experiments were performed to examine which of glasses prepared bycoating with the enzyme together with a gel matrix in the same manner asdescribed in Example 3 or by adding a different hydrolase other than thelipase exhibits more excellent performance to decompose variouscontaminants. Three kinds of samples, including a sample prepared byadding a lipase alone, a sample prepared by adding an amylase with alipase, and a sample prepared by adding a protease with a lipase, wereprepared to confirm a degree of removal of each contaminant by measuringa haze value. A contaminant prepared by mixing oil and starch wastransferred, and then the change in haze with time was observed. Theresults are shown in FIG. 9. A contaminant prepared by mixing oil andthe white of an egg was transferred, and the change in haze with timewas observed. The results are shown in FIG. 10. According to the twoexperiments, it was confirmed that the performance of removing the mixedcontaminants was improved when another hydrolase was added with thelipase, compared to when the lipase alone was added.

From the result, it was seen that the present invention can realizeanti-fingerprint performance by coating an enzyme on a surface of thesubstrate by a relatively simple method, and thus can be applied toalmost all substrates requiring the anti-fingerprint characteristic.

Contamination of display devices, appearances of the electronic devicesand building materials by fingerprints can be reduced usinganti-fingerprint coating according to the present invention.

While the invention has been shown and described with reference tocertain exemplary embodiments thereof, it will be understood by thoseskilled in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the invention asdefined by the appended claims.

What is claimed is:
 1. A method of forming anti-fingerprint coating,comprising treating a substrate with a composition comprising alipolytic enzyme.
 2. The method according to claim 1, wherein thelipolytic enzyme is a lipase.
 3. The method according to claim 2,wherein the composition further includes at least one enzyme selectedfrom the group consisting of a protease, an amylase, a cellulase, and alactase.
 4. The method according to claim 1, wherein the substrateincludes plastic or glass.
 5. The method according to claim 4, whereinthe plastic includes at least one polymer selected from the groupconsisting of polyester, polypropylene, polyethyleneterephthalate,polyethylenenaphthalate, polycarbonate, triacetylcellulose, olefincopolymers, and polymethylmethacrylate.
 6. The method according to claim1, wherein the lipolytic enzyme is introduced to a surface of thesubstrate by adsorption, covalent bonds, or encapsulation.
 7. The methodaccording to claim 6, wherein the covalent bond is formed through aprocess including treating the surface of the substrate having at leastone functional group selected from the group consisting of amino, amide,carboxyl, aldehyde, hydroxyl and thiol groups with a solution includinga bifunctional cross-linker; and dipping the substrate in a bufferincluding the lipolytic enzyme.
 8. The method according to claim 6,wherein the covalent bond is formed through a process including dippingthe substrate having an epoxy group at a surface thereof in a bufferincluding the enzyme.
 9. The method according to claim 6, wherein theencapsulation is performed by coating the surface of the substrate witha gel matrix, a microcapsule, a hollow fiber or a membrane, andintroducing the lipolytic enzyme.
 10. A substrate comprisinganti-fingerprint coating formed by the method according to any one ofclaims 1 to
 9. 11. The substrate according to claim 10, wherein theanti-fingerprint coating is formed on a surface of the substrate to havea thickness of about 20 nm to 200 μm.
 12. A product comprising thesubstrate according to claim
 11. 13. The product according to claim 12,which is a display device, an electronic device or a building material.